排序方式： 共有121条查询结果，搜索用时 31 毫秒
31.
Xue Hongchao Su Dehui Xu Fumin
Professor Research Institute of Coastal Ocean Engineering Hohai University Nanjing Doctor Dept. of Navigation Ocean Engineering Hohai University Nanjing Ph. D. Student Dept. of Navigation Ocean Engineering Hohai University Nanjing 《中国海洋工程》1995,(3)
- Combined with irregular wave-maker, the growing process of Wave Energy Spectrum in shallow water can be studied in wind wave channel on different water depth conditions, and its transformation characteristics and rules can be obtained. 相似文献
32.
High-Order Models of Nonlinear and Dispersive Wave in Water of Varying Depth with Arbitrary Sloping Bottom 总被引：4，自引：0，他引：4
Hong Guangwen
Professor Coastal Ocean Engineering Research Institute Hohai University Nanjing P. R. China. 《中国海洋工程》1997,(3)
High-order models with a dissipative term for nonlinear and dispersive wave in water of va-rying depth with an arbitrary sloping bottom are presented in this article.First,the formal derivations toany high order of μ(=h/λ,depth to deep-water wave length ratio)and ε(=α/h,wave amplitude todepth ratio)for velocity potential,particle velocity vector,pressure and the Boussinesq-type equations forsurface elevation η and horizontal velocity vector U at any given level in water are given.Then,the exactexplicit expressions to the fourth order of μ are derived.Finally,the linear solutions of η,U,C(phase ce-lerity)and C_g(group velocity)for a constant water depth are obtained.Compared with the Airy theory,excellent results can be found even for a water depth as large as the wave legnth.The present high-ordermodels are applicable to nonlinear regular and irregular waves in water of any varying depth(from shal-low to deep)and bottom slope(from mild to steep). 相似文献
33.
Zhang Yonggang Li Yucheng Teng Bin
Doctor Degree Candidate The National Key Laboratory of Coastal Offshore Engineering Dalian University of Technology Dalian
Professor The National Key Laboratory of Coastal Offshore Engineering Dalian University of Technology Dalian
Associate Professor The National Key Laboratory of Coastal Offshore Engineering Dalian University of Technology Dalian 《中国海洋工程》1995,(4)
The mild-slope equation derived by Berkhoff (1972), has widely been used in the numerical calculation of refraction and diffraction of regular waves. However, it is well known that the random sea waves has a significant effect in the refraction and diffraction problems. In this paper, a new form of time-dependent mild slope equation for irregular waves was derived with Fade approximation and Kubo's time series concept. The equation was simplified using WKB method, and simple and practical irregular mild slope equation was obtained. Results of numerical calculations are compared with those of laboratory experiments. 相似文献
34.
In this paper, the control performance is investigated of Circular Tuned Liquid Column Dampers (CTLCD) over torsional response of offshore platform structures excited by ground motions. Based on the equation of motion for the CTLCD-structure system, the optimal control parameters of CTLCD are given through some derivations on the supposition that the ground motion is a stochastic process. The influence of systematic parameters on the equivalent damping ratio of the structures is analyzed with purely torsional vibration and translational-torsional coupled vibration, respectively, The results show that the Circular Tuned Liquid Column Damper (CTLCD) is an effective torsional response control device. 相似文献
35.
The concrete-steel platform structure is rather complicated because it involves such materials as concrete, reinforcing bars, steel, and so on. K the traditional dimension optimization method is employed, the optimal design of the platform will meet many handicaps, even it cannot be implemented at all. The multilevel optimal design approach is an efficient tool for the solution of large-scale engineering structures. In this paper, this approach is applied to the optimal design of a concrete-steel platform, which is formulated as a system level optimal design problem and a set of uncoupled substructure level optimal design problems. The process of optimization is a process of iteration between system level and substructure level until the objective function converges. An illustrative example indicates that this method is effective in the optimal design of concrete-steel platforms. 相似文献
36.
Vertical structures of momentum exchange coefficient and sediment concentration are the keys in the research on estuarine and coastal suspended sediment transport. Based on the parabolic mixing length distribution pattern,the distribution pattern of vertical momentum exchange coefficient which is suitable for estuarine and coastal waters is constructed. A comparison with steady flow and measured momentum exchange coefficient during one tidal cycle in the Menai Strait of England shows that the result of this... 相似文献
37.
XIE Wenhui YANG Shilun
Graduate Student State Key Lab of Estuarine Coastal Sediment Dynamics Morphodynamics East China Normal University Shanghai P. R. China.
Professor State Key Lab of Estuarine Coastal Sediment Dynamics Morphodynamics East China Normal University Shanghai P. R. China. 《中国海洋工程》1999,(2)
-Based on historic topographic maps and field surveys,this paper mainly deals with the forma-tion and evolution of the Jiuduansha Shoal and the North Passage and South Passage in the ChangjiangEstuary.Jiuduansha Shoal originated from the partition of the south part of the Tongsha Shoal as the re-sult of connection of a flood channel and an ebb channel.The embryo of the North Passage was a floodchannel,and that of the South Passage was the lower reaches of the former South Channel.There weretwo basic kinds of change in erosion and accumulation since the formation of Jiuduansha Shoal:continu-ous change and periodic change.The former includes the broadening of the island area,accretion on thetidal marsh and tidal flat and downstream migration of the island.The latter includes cyclic erosion andaccumulation on the two river channel banks of the island and the North and South Passages.The islandand the two bifurcated river Passages interacted on each other in erosion and accumulation changes.Atpresent,the cou 相似文献
38.
The mild-slope equation is familiar to coastal engineers as it can effectively describe wave propagation in nearshore regions. However,its computational method in Cartesian coordinates often renders the model inaccurate in areas with irregular shorelines,such as estuaries and harbors. Based on the hyperbolic mild-slope equation in Cartesian coordinates,the numerical model in orthogonal curvilinear coordinates is developed. The transformed model is discretized by the finite difference method and solved by th... 相似文献
39.
Numerical Simulation of Spatial Lag Between Wave Breaking Point and Location of Maximum Wave-Induced Current 总被引：2，自引：0，他引：2
A quasi three-dimensional numerical model of wave-driven coastal currents with the effects of surface rollers is developed for the study of the spatial lag between the location of the maximum wave-induced current and the wave breaking point.The governing equations are derived from Navier-Stokes equations and solved by the hybrid method combining the fractional step finite different method in the horizontal plane with a Galerkin finite element method in the vertical direction.The surface rollers effects are considered through incorporating the creation and evolution of the roller area into the free surface shear stress.An energy equation facilitates the computation process which transfers the wave breaking energy dissipation to the surface roller energy.The wave driver model is a phase-averaged wave model based on the wave action balance equation.Two sets of laboratory experiments producing breaking waves that generated longshore currents on a planar beach are used to evaluate the model's performance.The present wave-driven coastal current model with the roller effect in the surface shear stress term can produce satisfactory results by increasing the wave-induced nearshore current velocity inside the surf zone and shifting the location of the maximum longshore current velocity landward. 相似文献
40.
In this paper,a numerical model for nonlinear wave propagation in currents is formulated by a set of enhanced fully nonlinear Boussinesq equations with ambient currents.This model is verified by comparison with the published results.Then the influence of currents on nonlinear focusing waves is studied by use of the numerical model.It is found that the effect of currents on the surface elevations at the focal location is negligible.Following currents can augment the maximum crest of focusing wave while decre... 相似文献